Hello Fahd
It is not possible to amend e-tickets.
What type of ticket is it? Supersaver or Point-to-Point? The latter you can cancel and repurchase.
The tickets must be issued on the person travelling, a ‘dfedexx’ looks rather suspicious and you may get into troubles during ticket check.
SBB cannot help you with tickets bought via Trainline. Simply purchase further tickets on sbb-tickets.cc/en
Kind regards,
Roland